Although the game of golf is a complex, often difficult endeavor, one aspect of the game remains fundamental; golf equipment must be kept within close proximity of a golfer as he/she moves about the course. Frequently, a golfer will get to the golf ball and discover that the lie and surrounding conditions are not as expected. If all of the clubs are not available for convenient selection a golfer will frequently make a low percentage shot with the wrong club rather than go to the trouble of retrieving the correct club. Therefore, it is desirable to have the entire club selection at hand in the near vicinity of the ball. It is also useful to have other contents of the golf bag, such as golf balls, umbrellas, and the like available for ready access.
Since the earliest beginnings of golf numerous methods have been devised to accomplish this. Among the most popular are; the golf carry bag, with or without a stand mechanism, (adapted to be lifted and carried by the golfer), the power cart (for transporting both the golfer(s) and clubs), and the hand-pulled cart. Although the carry bag is the most convenient means of transporting clubs it is also the most burdensome and straining to a golfer. Conversely, the power cart is clearly the least strenuous method of transporting one's equipment, unless caddies are available, a situation which is becoming less common. However, in using a power cart a golfer is foreclosed or discouraged from getting the exercise afforded while walking a round of golf (typically three to seven miles).
The hand-pulled cart ("pullcart") offers a golfer the ability to walk a round of golf while avoiding the uncomfortable consequences of carrying a golf bag. Unfortunately, while being generally less strenuous than carrying clubs, pulling a golf cart can also be demanding and put a strain on the golfer's back, in particular, especially when playing courses having hilly terrain. Consequently, numerous inventors have sought to solve this problem by developing self-powered or power-asserted golf bag carrying carts. Surprisingly, although several versions have achieved some success, none of the prior art in this field has been able to capture a significant share of the market for golf equipment transport devices. This is due in part to a variety of disadvantages inherent in the teachings. These disadvantages may be illustrated by a short discussion of the relevant art. Most of these devices may be grouped very generally into categories.
The first type is that which utilizes gasoline engines to empower a golf bag cart. An early example of this device is O. M. York Collapsible Power Drive Golf Bag Cart", U.S. Pat. No. 3,232,367. Devices of this nature may provide a collapsible powered golf bag cart, but they suffer the disadvantages of; creating noise in an environment not accepting of such noise, using an energy source susceptible to dangerous leakage during storage and/or transport, and/or adding unnecessary weight.
Another category of prior art includes devices designed to power a golf bag cart by a single electric motor, mounted to a gear box means coupled to a drive shaft. Most often, these types of devices utilize a central drive shaft to directly drive either or both rear wheels. Examples of this type of golf bag cart are disclosed by U.S. Pat. No. 3,907,056 and U.S. Pat. No. 3,952,821. Although devices of this type have the advantages of direct drive schemes they suffer disadvantages with respect to collapsibility and maneuverability. Golf bag carts driven off a common drive shaft cannot maneuvered easily because one wheel may not be slowed down or speeded up with respect to the other. Often this problem may be overcome by use of a differential gear. This solution, however, adds greater expense, weight and complexity to a product designed to be simple, lightweight and dependable. Moreover, direct drive of two wheels by a single draft shaft severely limits the collapsibility by requiring disassembly and reassembly of the direct drive scheme each time the golf bag cart is utilized. A further disadvantage of this type of golf bag cart is that the wheel base is limited to a set width. Often golfers may want a narrow wheel base in order to negotiate a narrow path. Therefore a cart which has adjustable features without jeopardizing the performance of the cart is preferred.
An effort to resolve many of the aforementioned deficiencies may be found in another category of prior art. The devices in this category attempt to drive each wheel independently by separate D.C. electric motors. An early device along this line is disclosed by Perlowin in U.S. Pat. No. 3,893,532. This device makes use of separate electric motors to drive each wheel of a golf bag cart. The Perlowin patent teaches a drive train utilizing an elastic drive belt design and is especially aimed at allowing rearward motion without damage to the motor structures. Furthermore, the two motors are shown to be commonly controlled and will operate at the same speed. Elastic belt systems are useful in avoiding drive train damage from irregularity in terrain, but suffer the disadvantage of being less efficient and more subject to wear then a true direct drive system. Furthermore, a proper gear box design will safeguard against any damage from irregular terrain, without requiring larger electric motors or heavy drive trains. Finally, this structure is not designed to be collapsible.
Another device along this line is disclosed by Nemeth in U.S. Pat. No. 4,106,583. Although this device also has the advantages of dual independent drive means, it suffers the disadvantage inherent in a frictional differential scheme. Frictional differential structures are known to be subject to breakdown over time.
Various commercial devices are also present in the golf marketplace. These include the "Powa Caddy" device, the "Condor" device by Auto-Caddy, Inc. of Los Altos, Cal., and the "Robo Caddy" device. These devices have achieved some success but have not sufficiently met the needs of potential users to the extent that they preclude improved entrants into the field.
Each known example prior art suffers from one or more of several disadvantages, such as: (1) The drive train is not direct; (2) both drive wheels are driven off a common drive shaft; (3) the gear box is not designed to withstand the random shocks and jolting experienced during operation on irregular terrain; (4) turning is impeded due to the inability to separately control the speed of each drive wheel; (5) the device is not adjustable to numerous positions; (6) the device is too heavy to be managed by many users, especially when lifting into a trunk of a vehicle; and/or (7) the device is not collapsible to a manageable size. Accordingly, a need remains in the marketplace for truly effective, collapsible, easy to use self-powered golf bag cart devices.